Power plant



April l, 1941. R. PATERAs PESCARA POWER rlLANT Filed NOV. 18 193B N Q 5g iq um QJ m t @i oog y lu Us' Patented Apr. 1, 1941 Y Raul Patel-as Pescara, Paris, France Application November 18, 1938, Serial No.,241,273

' In France October 15, 1934 (ci. ca -11) 6 Claims.

The present application is a continuationin part of my applicationlSer. No. 44,982, filed Oct. 14, 1935, Patent No; 2,152,972 of April 4, 1939.

My invention relates" to systems including sieveral motor-compressors, and in particular motorcompressors of the free piston type, and a receiving machine common to these motor-compressors.

The object of the present invention is to provide a system of this type which is better adapted to meet the requirements of practice.

According to the essential feature of the present invention, in a system of the type above dethe atmosphere, I provide means for stopping or scribed, I provide means for bringing the motorcompressors into and out of action individually, according to the needs, and preferably -in an automatic manner as a function of the variations` of the load of the receiving machine.-

Other features of the present invention will result from the following detailed description of a specific embodiment thereof.

A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which:

' Fig. l is a diagrammatic elevational view, partly in section, showing a system accordingfto the invention including three motor compressors adapted to be associated with a single turbine, and the means for controlling said compressors;

Fig. 2 is a detail view showing the means for starting or stopping a compressor.

As above stated, the object of'thenvention is ing closed, the reduction of the delivery pressure of the corresponding compressor I.

Discharge valves t1, 42 and 42 areprovided respectively on the corresponding conduits 31, 32,

and 33, so as to allow a variable part of the compressed gas to escape into the atmosphere, this variable discharge being adjustable, preferably, according to the load of the turbine.

According to the essential feature of the present invention, in order to reduce to a minimum the amount of compressed fluid which is lost into starting one or several compressbrs individually, so as to permit of adjusting the power Supplied in accordance with considerable variations of the load of the turbine.

In the embodiment illustrated by the drawing, each compressor is automatically controlled in response to the pressure existing in the discharge conduit of a preceding compressor, said pressure being transmitted through conduits such asv 252 and 252, while the control conduit 251 of generator I1 is in communication with a source of compressed air located on theoutside. Each of the compressors is started when the pressure in the corresponding control conduit reaches a predetermined value. inversely, each of these com;- pressors is automatically stopped when the pres-v .sure transmitted through the corresponding conu to provide a plant including at least two compressed gas generators adapted to feed compressed gas to a `receiving machine, for instance of the turbine type. f

Concerning the compressed gas generators,v

n duits 31, 32, and 373 to the inlet chambers 21, 22 and 22 of a turbine 2. Y I

In order to ,obtain a good working of the compressors, I may provide, for instance between each compressor I and the corresponding conduit e 3, a valve such as I3 (Fig.` 2) automatically operated by a piston Il subjected-to the action of the pressure existing in said conduit 3 and to the action of an antagonistic spring I5, in such manner thatfif the pressure is zero or insufficientl in v said conduit 3, valve I3 prevents, through its betrol conduit drops below a predetermined value.

Fig. 2 shows one of the compressors, to wit compressor I2,'i,n cross section. For the sake of simplicity of showing, this compressor includes only one piston group.

This piston group consists of three piston elements 63, 64I, and 65. Part 65 forms the motor piston which works in a motor cylinder 66. Part 64 forms the compressor piston which works in the compressor cylinder formed by the casing' thereof and dividing walls such as 83. The space below piston part 54 communicates with the atmosphere through opening 8l. n piston for the compensating air cushion within the compensating cylinder 5l. Air compressed in a space above piston part 64 passes through check valve 86 and reservoir 85 into the space surrounding motor cylinder 66 and thence to the outlet of the compressor. Cylinder 66 communicates with this space by openings 82. The starting of the compressor is produced by injecting starting air under pressure into the compensating cylinder, which is provided, for this purpose, with a starting valve 68 rigid with a piston 69 movable in an\extension of cylinder 61. A spring I0 acts" on saidpiston 69 and con- 4 Part 63 forms the lstantly tends to maintain valve 68 in the closed position.

In the upper part of the compressor casing, there is a slide-valve including two pistons 12 and 13 movable in a cylindrical chamber 18. The

' portion of said chamber ahead of piston 12 communicates directly with conduit 252 (directly connected with the discharge conduit 31 of the preceding compressor Il) Slide-valve 'I2-13 is subjected tothe opposing action of spring 11.

Cylindrical chamber 18 communicates with an annular chamber 1I (surrounding cylinder 61).

through a hole 15 along which piston 12 is movable.-

Chamber 18 further communicates through a hole 16 with the cylindrical extension 61 in lwhich piston 69 is movable, above said piston.

Holes i9 and 80 connect the space between piston 69 and valve 68 with annular chamber 1 I.

Finally, cylindrical chamber 18 is provided with a hole 14 opening into the atmosphere and adapted to be uncovered by piston 'I3 when the'latter is pushed into extrem-e position toward the right against the action of spring 11. o

I will i-lrst describe the operation of this starting device.

sure these actions balance each other, and valve" 58 remains closed under the effect of the pressure in question acting upon the upper fac'eof said valve and of spring 1I).

When the pressure in conduit 252 exceeds a given value because of an increased load on the driven machine, slide valve I2-13 is pushed to' ward the right, the space between pistons 12 and 13 ceases to-.be connected with conduit 252 and, on the contrary, through hole 14, it is connected with the atmosphere. Therefore through hole 16, the upper face of piston 69 communicates with the atmosphere. On the other hand, the

v Vpressure acting upon the under -face of piston 69 exerts upon said piston a force greater than that exerted bysaid pressure on the upper face of valve 68, since the area of piston 69 is considerably greater than that of valve 68. And the difference of these forces is greater than the action of spring 10. so that said valve 68 islifted from its. seat. The compressed gas then enter cylinder 61. and starts the compressor. l'

It will be noted that when the pressure in conduit 252 drops below the value above considered, because of the decrease in the load on the driven machine the device Works in the reverse order and closes back valve 68, thus stopping the compressor.

Now, if the load of the turbine drops, only the 'i discharge valve of the generator which is the last to.be started can be operated, the other dis- 'charge valves 41 and 42 being then locked; in their jected, on one of its faces, to the pressure eirist-V ing in the discharge conduit, 32 or 32, of the next generator I2 or I 3,- and, on its other face, to the action of a spring 21. Each piston 26 drives a slide valve 28 which according to its position,

for instance as oil vunder pressure, said rinletv communicating with a cylinder 29, in which the action of said fluid on a piston 30, balanced by the action of a spring 3|, serves to" operate the corresponding valve 41 or 42. The distribution of oil under pressure fed by a pump 32, driven for instance by the turbine, can be adjusted by means of a slide-valve which may be ,operated l0 manually but which, advantageously, is coupled with the governor I0 of the turbine. For instance, this distributing member'consists ot a slide valve such as shown at 33. According to the position occupied by said slide valve 33, either the feed conduit 34 for cylinders 2B is connected either with the discharge conduit 35 of the pump, or with the exhaust conduit 36, or communication between these conduits 34 and 35 is wholly stopped.

If generators I1, I2 and I3 are working and the load of the turbine drops, the action of governor I0 causes conduits 34 and 35 to be 'connected together and oil under pressure is fed to the cylinder 29 corresponding to valve d. which is opened by the corresponding piston 30. As a consequence, the pressure drops in conduit 33 and when valve 43 is fully opened, the pressure in said conduit is insufcient for keeping the slide valve 28 of valve 32 in closed position. Due to 30 the opening of'this slide valve, oil under pressure is fed to the corresponding cylinder` 23, which ensures the opening of valve 62, It follows that the pressure in conduit 32 decreases and that, in view of the transmission of said pressure 35 through conduit 253, compressor I3 is caused to stop. Said generator of compressed gas can be brought back into operation only when valve 42 is fully closed, which takes place when the load on the turbine increases and slide valve 33, driven by governor I0, closes conduit 35 and-connects conduit 34 with the emptying conduit 36. It follows that the pressure ceases to act in cylinder 29 the piston ofrwhich controls valve $2, said piston being brought back into 'the closed posi- 45 tion by the corresponding spring 3i. 4

In a general manner, while I have, in theabove description, disclosed what I deem to be practical and efcient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition Jand form of the parts as comprehended within the scope of the accompanying claims.

' What I claim is:

1. In a power plant comprising a plurality of free piston motorY compressors, a receivinganachine, and means to conduct uid under pressure from each of said motor compressors to said machine, each of said motor compressors including a fluid pressure starting device, means controlled automatically by variations in the load on the machine to operate various of said starting devices as the load increases to increase the number of motor compressors in operation, and to stop various of said motor compressorsl as the load `decreases to decrease the number in operation. f

2. In a power plant comprising a plurality of free piston motor compressors, a receiving machine, and means to conduct fluid under pressure from each ,of said motor compressors to said machine, each of said motor compressors including a fluid.pressure starting device, meansy controlled automatically by variations in the delivery pressure of the compressors to operate various of said starting devices as the load increases to increase the number of motor compressors in operation, and to stop various of said motor compressors as the load decreases to decrease the number in operation.

3. In a power plant comprising a plurality of free piston motor compressors, a turbine, and means to conduct fluid under pressure from each of said motor compressors to said turbine, each of said motor compressors including a fluid pressure starting device, means controlled automatically by variations yin the delivery pressure of the compressors to operate various of said` starting devices as the load increases to increase the number of motor compressors in operation, and to stop various of said motor compressors as the load decreases to decrease the number in operation.

4. In a power plant comprising a plurality of v free piston motor compressors, a turbine, and

means to conduct fluid under pressure from each of said motor compressors to said turbine, each of said motor compressors including fluid pressure'starting apparatus, a governor connected to said turbine and driven thereby, and means operated by said governor in response to variations in the speed of the turbine to operate various of said starting devices as the load increases to increase the number of motor compressors in operation, and to stop various of said motor compressors as the load decreases toy decrease the number in operation.

5. In a power plant comprising a plurality of free piston motor compressors, a. turbine having a plurality of inlet chambers, and a plurality of -v delivery conduits for conducting fluid under pressure from said motor compressors to the respective inlet chambers of said turbine, each of said motor compressors including a fluid pressure starting device, means in each delivery conduit to discharge fluid therefrom, a governor connected to said turbine and driven thereby, means operated by said governor in response to variations in the speed of the turbine tao-operate said discharging means, and means controlled automatically by variations,` in the pressure in the delivery conduits to operate various of said starting devices as the load increases to increase the number foi motor compressors in operation, and to stop various of said motor compressors as the load decreases to decrease the number in operation. y

6. In a power plant comprising a plurality of free piston motor compressors, a receiving' machine, and a plurality of delivery conduits for conducting fluid under pressure from each of said motor compressors to said machine, each of said motor compressors including a uid pressure starting apparatus, means connecting the starting devices of at least lsome of the motor compressors to the delivery conduits of other motor compressors, whereby upon variations in the load on the machine to operate various of said starting devices as the load increases to increase the number of motor compressors in operation, and to stop various of said motor compressors as the load decreases to decrease the number in operation.

RAUL PATERAS PESCARA. 

